Child labor during World War II

Many states had induced this crisis by suspending or relaxing their child labor laws, but even those still operative proved ineffective.  By one estimate 900,000 children between twelve and eighteen were working in defiance of the law in their state.  Philadelphia saw a decline of 13 percent in high school attendance,while in Oakland 15 percent of the children under sixteen had gone to work.  Nothing demonstrated the failings of the educational system more than the irony that many of these kids earned more than their teachers did.

That is from the new Maury Klein book A Call to Arms: Mobilizing America for World War II.